Flow can escape from a hydraulic circuit through external or internal leakage. External leakage such as a burst hose can be easy to find. Internal leakage can occur in the pump, valves or actuators and can be more difficult to isolate. The detection and isolation of hydraulic oil leakage can be an economic and safety challenge in the field of hydraulics. For example, as a hydraulic actuator is used over time, the piston seal that closes the gap between the moveable piston and the cylinder wall wears. This results in the hydraulic oil eventually being able to flow around the piston and between the cylinder chambers. Although no hydraulic oil is lost from the hydraulic circuit, the dynamic performance of the hydraulic system is affected, since only a portion of the flow delivered to the actuator is available to move the piston against the load. Therefore, there is a need for the development of reliable techniques and systems for leak detection and isolation in hydraulic systems.